The International Maize and Wheat Improvement Center (CIMMYT) is an internationally
funded, nonprofit scientific research and training organization. Headquartered in Mexico,
the Center is engaged in a worldwide research program for maize, wheat, and triticale, with
emphasis on food production in developing countries. It is one of 13 nonprofit international
agricultural research and training centers supported by the Consultative Group on
International Agricultural Research (CGIAR), which is sponsored by the Food and
Agriculture Organization (FAO) of the United Nations, the International Bank for
Reconstruction and Development (World Bank), and the United Nations Development
Programme (UNDP). Donors to the CGIAR system are a combined group of 40 donor
countries, international and regional organizations, and private foundations.

CIMMYT receives core support through the CGIAR from a number of sources, including the
international aid agencies of Australia, Austria, Brazil, Canada, China, Denmark, Federal
Republic of Germany, Finland, France, India, Ireland, Italy, Japan, Mexico, the Netherlands,
Norway, the Philippines, Spain, Switzerland, the United Kingdom, and the USA, and from
the European Economic Commission, Ford Foundation, Inter-American Development Bank,
OPEC Fund for International Development, UNDP, and World Bank. CIMMYT also receives
non-CGIAR extra-core support from Belgium, the International Development Research
Centre, the Rockefeller Foundation, and many of the core donors listed above.

Part One. The Partial Budget
Identifying Variable Inputs
Field Price and Field Cost of Purchased Inputs
Field Prices of Fertilizer and Nutrients
Equipment
Labor
Total Costs That Vary
Pooling the Results From the Same
Recommendation Domain
Assessing Experimental Results Before
Economic Analysis
Adjusted Yield
Field Price
Field Price
Gross Field Benefits
Partial Budgets
Partial Budgets
Including All Gross Benefits in the Partial Budget

The exercises in this workbook have been developed over the past several years
for various courses and workshops on economic analysis offered by the CIMMYT
Economics Program. They build upon a set of exercises developed by Larry
Harrington, Exercises in the Economic Analysis of Agronomic Data (CIMMYT
Economics Program Working Paper, 1982). We have modified some of those
exercises and added many new ones. All have been tested extensively, and we feel
they offer good practice for learning the procedures described in the manual, From
Agronomic Data to Farmer Recommendations. We wish to thank our colleagues in
the CIMMYT Economics Program and the participants in our training activities for
their contributions to these exercises.

We also wish to thank many other people who helped produce this workbook.
Numerous drafts were typed with great efficiency by Maria Luisa Rodriguez and
Beatriz Roj6n. The workbook has been improved by the editing of Kelly Cassaday
and the imaginative design of Anita Albert. Typesetting, layout, and production
were done by Silvia Bistrain R., Maricela A. de Ramos, Miguel Mellado E., Rafael
De la Colina F., Jos6 Manuel Fouilloux B., and Bertha Regalado M.

Robert Tripp
Gustavo Sain
CIMMYT Economics Program

I Inrduto

How to Use This Workbook

This workbook is designed to be used with the manual, From Agronomic Data to
Farmer Recommendations, Completely Revised Edition, CIMMYT Economics
Program (1988). It can be used in the classroom or for individual study.

The exercises are presented in the same order as the themes of the manual. Each
exercise is keyed at the bottom of the page to the appropriate chapter or section
and pages of the manual.

A separate answer booklet is available. It is best to work through an entire
exercise before checking the answer in the booklet.

Abbreviations Used in the Workbook

The $ sign is not intended to represent any particular currency, and several
different currencies are assumed in the exercises.

For each of the following pieces of information derived from on-farm research,
indicate who is the most appropriate audience: researchers, farmers, or
policymakers.

a. The most economic amount of fertilizer for maize in this area is 2 bags of
18-46-0 and 11/2 bags of urea per hectare.

b. The efficiency of fertilizer utilization in this area is limited by acid soils.

c. Fertilizer is most efficient if it is applied within 3 weeks of planting, but
fertilizer is often not available in the government shop until at least 1 month
after planting.

. 1. .- a

S rch, pp. 1-3

I Exercise 1

I Exercise 2

Goals of the Farmer

Determine which of the farmer's goals or interests (listed in the second column) is
implied in each question in the first column.

Goal/Interest

1. If I change my weeding
practices, will my chance of
failure in a year of low
rainfall increase or decrease?

2. If I change my weeding practices,
how much more yield will I get,
and how much more money will I
have to spend?

3. If I change my weeding practices,
will I have to make many other
changes as well?

4. If I change my weeding practices
in maize, will I still be able
to grow beans?

A. In order to provide for the
the needs of their families,
farmers manage systems of
various crops and animals.

B. Farmers are interested in
the economic return from
a new practice.

C. Farmers are concerned about
risks.

D. Farmers are interested in
making stepwise changes in
their practices.

--Goals of the Farmer, pp. 4-5

Question

U

On-Farm Experiments

Decide whether each of the following experiments is designed so that an economic
analysis of the results is possible. If an analysis cannot be done, what changes in
the experiment would make it possible?

a. A trial in which 4 levels of nitrogen are tested, including the level used by
farmers. The nonexperimental variables (variety, seeding rate, weed control,
etc.) are representative of farmers' practice.

b. A trial in which 5 levels of nitrogen and 3 levels of phosphorus are applied to
the crop. A treatment is included that represents farmers' current fertilizer
practice. Researchers prepare the plot where the experiment will be planted
and use seeding rates, weed control, and pest control methods identical to
those used on the experiment station.

c. An experiment that examines 2 new varieties and 2 new seeding rates (above
and below the farmers' usual rate). Farmers prepare the plot and control the
weeds and insects following representative practices.

On-Farm Experiments, pp. 5-7

I Exercise

Execis 4A

U

Experimental Locations and Recommendation Domains

The farmers of a tentative recommendation domain plant a maize-maize rotation
and prepare their fields with tractors. Their maize plants show evidence of
nitrogen deficiency. Which one(s) of the fields listed below would be appropriate
for a fertilizer experiment for the domain?

Previous crop
Maize
Maize
Tobacco
Maize

Method of land
preparation
Ox plow
Tractor
Tractor
Tractor

Field size (ha)
3
2
1
15

Experimental Locations and Recommendation Domains, pp. 7-8

Field

U

The Partial Budget

Fill in the blanks in the partial budget below with the titles of budget items (a-c)
or numbers (d-f).

Average yield (kg/ha)

(kg/ha)

Gross field
benefits (S/ha)

Cost of fertilizer (S/ha)

Cost of labor to apply fertilizer (S/ha)

(S/ha)

(S/ha)

The Partial Budget, pp. 9-11

Treatment

2
(100 kg
urea/ha)
2,100

1,680

840

80

20

100

1
(No
fertilizer)
1,500

1,200

600

0

0

0

600

3
(200 kg
urea/ha)
2,400

1,920

960

160

20

Exercise 5

I Execise

Marginal Analysis

Calculate the marginal rate of return between Treatment 1 and Treatment 2.

Treatment

Total costs that vary (S/ha)

Net benefits (S/ha)

Marginal Analysis, pp. 11-12

150

430

2
200

470

Variability

Each of the following situations is an example of how variability affects the
interpretation of experimental results. For each situation, indicate the type of
variability:

Insecticide A costs $10 for a 2.5-kg bag. Treatment 1 in an experiment requires
5 kg/ha of Insecticide A and Treatment 2 calls for 10 kg/ha of Insecticide A.

a. What is the field price of Insecticide A?

b. What is the field cost of Insecticide A in Treatment 1?

c. What is the field cost of Insecticide A in Treatment 2?

Costs That Vary, pp. 13-14

I E c s

Field Prices of Fertilizer and Nutrients

The following data are from one research area:
Cost of 45 kg ammonium sulphate in shop
Cost of 45 kg triple superphosphate in shop
Cost of transporting a 45-kg bag from shop to farm
(Ammonium sulphate is 21% N; triple superphosphate is 46% P205.)

Calculate:
a. The field price of ammonium sulphate

b. The field price of triple superphosphate

c. The field price of N

d. The field price of P205

Purchased Inputs, pp. 14-16

U

$740
$1,620
$95

Equipment

Two types of land preparation were examined in an experiment.

Treatment 1: One plowing and two harrowings with a tractor
Treatment 2: Plowing with a horse

Data
Tractor plowing $200/ha

Tractor harrowing $100/ha

Horse plowing $ 35/day (horse can plow /4 ha in one day)

Calculate the costs of land preparation for each treatment.

Equipment and Machinery, p. 16

E xer ise 1 1

Labor

In the analysis of a weed control experiment, it was found that five 6-hour days
are required to hand weed 1 acre (0.4 ha). The local wage rate was $35 for a
6-hour day, and the farmer was also expected to provide the laborer with one
meal, valued at about $10. Calculate the cost of weeding 1 hectare.

Labor, pp. 16-18

Exercse 1

Total Costs That Vary

Calculate the total costs that vary for each of the following experiments.

A variety by fertilizer experiment was planted in one research area consisting of
two recommendation domains. Recommendation Domain A was defined as those
farmers who had very sandy soils, while Recommendation Domain B consisted of
those farmers who had clay-loam soils.

Yield data from nine locations are presented below. Find the average yields for
each treatment for each recommendation domain.

Treatment yield (kg/ha)

Location

1
2
3
4
5
6
7a/
8
9

Recommendation
domain

A
A
B
A
B
B
A
B
A

1
Local
variety,
no
fertilizer

960
1,010
1,820
570
2,270
1,900
200
2,430
890

2
Improved
variety,
no
fertilizer

910
620
1,650
490
2,420
1,740
200
2,010
620

3
Local
variety
with
fertilizer

1,560
1,820
2,240
980
2,750
2,190
200
2,740
1,480

4
Improved
variety
with
fertilizer

1,380
1,450
2,920
820
3,300
2,840
200
3,210
1,370

a/ Trial lost due to drought. Yield estimated to be 200 kg/ha across treatments.

Recommendation Domain A

Treatment

Average yield
(kg/ha)

Recommendation Domain B

Treatment

Average yield
(kg/ha)

Pooling the Results From the Same Recommendation Domain, pp. 20-21

U

Assessing Experimental Results Before Economic Analysis

In one research area, farmers sometimes planted late because they had to wait to
rent an ox plow. Researchers decided to test the alternative of partial tillage using
an ox-drawn ripper tine, which would open a furrow into which farmers could
plant. The tine made tillage and planting quicker, but more weeding was required
after tillage. Experiments in eight locations gave the following yield results:

Method

Plow
Tine

Average yield (kg/ha)

3,258
3,015

After carefully examining the data and results of the statistical analysis, and
reviewing the observations made at each location, agronomists concluded that
there was no yield difference between the two treatments.

Use the following information to decide which
farmers.

practice should be recommended to

Method

Plow

Tillage time

Equipment and labor for
tillage

Planting time

Weeding time

Wage rate for planting or
weeding

2 days/ha

$5.60/day

5 days/ha

20 days/ha

$1.20/day

Tine

1 day/ha

$4.75/day

2 days/ha

35 days/ha

$1.20/day

Assessing Experimental Results Before Economic Analysis, pp. 21-22

I^^^^^^^^^ Ex ercise^^^^^ 15 ^^^^^^^^^^

Adjusted Yield

Because of their careful application of fertilizer in an experiment on potatoes,
researchers decided to reduce yields by 5% to estimate the yields that would be
expected if farmers had managed the fertilizer. They also estimated that the effect
of small plot size warranted another 5% reduction. Harvesting date and method
were the same as those of the farmers. Thus the experimental yields were
adjusted downward by 10%.

Use the data presented below to calculate the average yields and the adjusted
yields for each treatment.

In a maize-growing region, farmers received $80 for a 50-kg bag of grain in the
local market. The cost of transporting a 50-kg bag of grain to market averaged $5.
Harvesting took about 8 days per hectare, and average yields in the area were
2,400 kg/ha. A worker was able to shell about 400 kg of maize in one day. The
wage rate was $40 per day. What is the field price of maize?

Field Price of the Crop, pp. 25-27

Exercise

Field Price

Wheat farmers harvested their crop with rented combine harvesters.
The combine operators charged $550/ha, regardless of yield. Farmers sold their
wheat at a government warehouse in town and had to pay trucking costs of
$0.16/kg. The official buying price of the wheat was $2.20/kg, but because of
discounts for quality farmers usually received 5% less than the official price.
Average wheat yields in the area were 2,000 kg/ha. What is the field price of
wheat?

Field Price of the Crop, pp. 25-27

m

I Note

Exercise

Gross Field Benefits

The average yields from a maize experiment are shown below.

Treatment

Average yield (kg/ha)

1,740

2
2,430

3
1,420

4
2,790

Because of plot size, differences in management, and time of harvest researchers
decided to adjust yields from all treatments downward by 20%. Maize was sold in
town for $12.00/kg. Transport costs from farm to town were $0.60/kg and the cost
of harvesting and shelling was $0.80/kg.

Fill in the first three lines of the partial budget.

Treatment

Average yield (kg/ha)

Adjusted yield (kg/ha)

Gross field benefits (S/ha)

Gross Field Benefits, p. 27

U9

Partial Budgets

Complete the partial budget for an insecticide experiment, using the following
data.

Treatment

Insecticide A
(One application = 8 kg/ha,
as a foliar insecticide)

1 application

2 applications

1 application

Data
Sale price of maize
Harvesting cost
Shelling cost
Transport from field
to sale point
Cost of labor
Price of Insecticide A

An experiment looked at the response of wheat to different levels of nitrogen. Use
the following information to calculate gross field benefits for all of the treatments
of the experiment, and complete the partial budget.

* Both grain and straw are important products for the farmers.

* Farmers sell their wheat immediately after harvest for $4.00/kg. Harvesting and
threshing costs total $0.30/kg, and transport to place of sale costs $0.20/kg.

* Wheat straw is baled and sold as animal feed. Farmers receive $5.10 for a 18-kg
bale. The purchaser of the straw, not the farmer, pays transport costs. The
farmer pays the cost of baling ($0.60/bale).

It is estimated that researchers obtain higher wheat yields than farmers because
researchers manage the crop with greater precision and harvest earlier (15%
adjustment). It is estimated that researchers get higher straw yields as well,
because of precise management (10% adjustment).

The field price of nitrogen is $10/kg. The fertilizer is all applied at planting, at a
cost of $200/ha.

a. To estimate the minimum rate of return acceptable to farmers, a range of 50%
to 100% per crop cycle may be considered acceptable, if no other information
is available.

For each of the following possible recommendations, indicate whether a
minimum rate of return closer to 50% or 100% would be most appropriate.

1. Herbicides, where farmers are currently weeding with hoes

2. A new herbicide, where farmers are already using herbicide

3. A change in seeding rate (but same seeding method)

4. Using a seed drill, where farmers are currently seeding by broadcasting

b. In one research area it was common to borrow money from shopkeepers for
agricultural purposes. The shopkeepers charged a flat rate of 8% per month. If
the agricultural cycle is about 6 months, what would be a reasonable estimate
for a minimum rate of return?

c. Farmers in a certain region have access to a government bank that caters to
small- and medium-scale farmers. The bank's loan rate is 24% per year. The
bank also charges a flat rate of 15% of the value of the loan for crop insurance
and a 10% service charge. If farmers can get loans to buy fertilizer, and if
there are about 5 months from planting to the sale of the harvest, what would
be a reasonable estimate for a minimum rate of return?

The Minimum Acceptable Rate of Return, pp. 34-37

Exercise 25 1

^^^^^^^Exe^^rci^Kfse 26A ^^^^^

Interpreting Net Benefit Curves

The following are the results of 40 fertilizer trials planted over 3 years in one
recommendation domain. There is a significant response to both nitrogen and
phosphorus. Conduct a dominance analysis, draw the net benefit curve, and use
marginal analysis to make a recommendation to farmers. Check the analysis by
using the method of residuals. The minimum rate of return is assumed to be 50%.

Treatment

1.a/
2.
3.
4.
5.
6.
7.
8.

N
(kg/ha)

40
40
80
80
120
120
80
120

P205
(kg/ha)

0
40
0
40
0
40
80
80

Total costs
that vary($/ha)

99
190
198
277
285
364
372
451

Net benefits
($/ha)

500
480
610
520
675
580
420
350

a/ Farmers' practice

Using Marginal Analysis to Make Recommendations, pp. 38-48

U

U0

Interpreting Net Benefit Curves

The following are the results of 5 nitrogen by phosphorus experiments planted in
1 year in a single recommendation domain. Statistical analysis shows significant
response to both nitrogen and phosphorus. Conduct a dominance analysis, draw
the net benefit curve, and use marginal analysis to help decide what levels of
fertilizer researchers should experiment with next year. Check the analysis by
using residuals. The minimum rate of return is assumed to be 100%.

Nitrogen by phosphorus experiment

Treatment

1.a/
2.
3.
4.
5.
6.
7.

N
(kg/ha)
0
50
100
50
100
100
100

P205
(kg/ha)

0
0
0
50
50
75
100

Total costs
that vary
($/ha)
0
50
100
100
150
175
200

Net
benefits
($/ha)
800
950
965
945
1,065
1,075
1,040

a/ Farmers' practice

Using Marginal Analysis to Make Recommendations, pp. 38-48

Exrcse26

I Exerise 26

Interpreting Net Benefit Curves

The following are results of 25 trials planted over 2 years in one recommendation
domain. The trials were designed to look at the effects of improved variety, weed
control, and fertilization. If the minimum rate of return is 100%, what should be
recommended to farmers? If farmers are likely to adopt recommendations in steps,
what should be recommended to farmers?

Weed
Treatment Varietya/ controla- Fertilizationa/

1 0 0 0

2 1 0 0

3 1 1 0

4 1 0 1

5 1 1 1

a/ 0 = Farmers' practice, 1 = Improved practice)

Total costs
that vary
($/ha)

Net
benefits
($/ha)

0 625

10 685

72 807

79 782 D

907

S900

800

700

197%

3
4

( 2
600%

600

100

Total costs that vary (S/ha)

Using Marginal Analysis to Make Recommendations, pp. 38-48

Marginal
rate
of return

600%

197%

145%

Interpreting Net Benefit Curves

In one recommendation domain researchers planted 6 insecticide experiments.
The response to insecticide was statistically significant. The results of the partial
budget are shown below. If the minimum rate of return is 100%, what should
researchers do the following year? Check the interpretation by calculating
residuals.

Treatment

1. No insect control a/

2. Insecticide A (at planting)

3. Insecticide B (granular)

4. Insecticide A + Insecticide B

Total costs
that vary
($/ha)

Net
benefits
($/ha)
722

730

738

752

Marignal
rate of
return

25%

267%

44%

a/ Farmers' practice

750

740

730

720
f

10 20 30 40 50 60 70
Total costs that vary (S/ha)

Using Marginal Analysis to Make Recommendations, pp. 38-48

I Eerise26

Exercise 26E I

Interpreting Net Benefit Curves

Researchers planted 10 seeding method by fertilizer experiments in wheat in one
recommendation domain where farmers were broadcasting their wheat and
applying about 40 kg N/ha. The results of the marginal analysis are shown below.
The minimum rate of return is 100%. What should researchers recommend to
farmers?

Seeding Fertilization
method Kg N/ha Kg P205/ha

60 30

1 Broadcast

2 Drill

3 Drill

Total costs
that vary
($/ha)

240

287

319

Net
benefits
($/ha)

630

756

Marginal
rate of
return

172%

141%

(Farmers' practice = broadcast seeding and 40 kg N/ha)

750

710

670

630 V
S240
240

172%

280
Total costs that vary (S/ha)

300

320

Using Marginal Analysis to Make Recommendations, pp. 38-48

Treatment

U

U

Partial Budgets and Complete Budgets

To demonstrate the value of partial budgets, perform dominance analysis and
marginal analysis on the following two data sets drawn from the same set of
experiments. Yields and gross benefits are identical for both data sets. The only
difference is that Data Set 2 also includes costs that do not vary between
treatments. Assume a minimum rate of return of 100%.

In one research area maize farmers were controlling weeds by hand. Researchers
were considering experimenting with a herbicide, which they felt was more
effective. Calculate the yield increase required to make herbicide adoption
acceptable to farmers.

Ten on-farm fertilizer trials in wheat looked at the farmers' practice, which is not
to fertilize, and an alternative practice of applying 80 kg/ha each of N and P205.
Farmers plant their wheat in January or February in rotation after maize or
barley.

Review the data from the field book and decide which locations should be
eliminated from the analysis. In each case, give an explanation.

Calculate the average yields for the two treatments that would appear in the
partial budget.

Table 1 shows the results of three exploratory 24 factorial experiments planted in
maize. In these experiments, the four factors were tillage, plant density, nitrogen,
and phosphorus. For each of the four factors, two levels were used: the farmers'
practice and an alternative. The experiment had a total of 16 treatments.

Use the information on the statistical analysis in Table 2 to decide how to analyze
the data. Farmers currently prepare their fields with tractors, plant at 40,000
plants/ha, and use no nitrogen or phosphorus fertilizer. On the basis of the
economic analysis of these exploratory experiments, make suggestions regarding
the importance of continuing to experiment with each of these four factors the
following year.

The results of an experiment planted in 24 locations over 2 years are presented in
Table 1. The purpose of the experiment was to verify the advantages of improved
practices in weed control, plant population, and higher levels of fertilization, in
comparison with the farmers' current practice.

Table 1
Data from 36 Verification Experiments

Average yield (kg/ha)
Average net benefits ($/ha)
Total costs that vary ($/ha)

Before making a recommendation, the researchers have decided that they will do
a minimum returns analysis on the data. The first step is to calculate net benefits
for individual locations. The yield data from locations 1 and 2 are presented in
Table 2 as examples. Use these yields to calculate net benefits. Use the data on
total costs that vary from Table 1. The field price of maize is $1.60/kg and the
yield adjustment in the experiments is 10%.

Table 2
Yields (kg/ha) by Location

Treatment

Location

24
Average

2,706
3,542

1,118
1,825

3,677
4,188

1,792
2,617

4,319
4,139

3,302
3,098

Net Benefits (S/ha) by Location

Location

Minimum Returns Analysis, pp. 67-70

Exercse 3

Minimum Returns Analysis

The rest of these calculations appear in Table 3. Use these data to do a minimum
returns analysis and decide which treatment would be most appropriate to
recommend to farmers.

1. The yield results of 10 fertilizer experiments in wheat are shown below. If the field
price of wheat is $5.50/kg, calculate gross benefits and net benefits and do a
marginal analysis on the data. If the minimum rate of return is 100%, what would
be the recommendation? (Farmers currently use no fertilizer.)

Adjusted
yield
Kg N/ha Kg P205/ha (kg/ha)

0 1,784

0 2,564

80 2,763

3,340

2 150

75 160

Gross field
benefits
(S/ha)

Total costs
that vary
(S/ha)

Net
benefits
(S/ha)

Marginal
rate of
return (%)

0

2,803

3,253

5,105

2. The government is considering increasing the price of wheat. If this should
happen, the field price of wheat would be $7.40/kg. Use the new field price to
recalculate the gross benefits and net benefits. Identify a suitable
recommendation with the higher price of wheat.

Adjusted
yield
Kg N/ha Kg P205/ha (kg/ha)

2 150

3 75

4 75

Gross field
benefits
(S/ha)

0 1,784

0 2,564

80 2,763

160

Total costs
that vary
(S/ha)

Net
benefits
(S/ha)

Marginal
rate of
return (%)

0

2,803

3,253

5,105

3,340

Sensitivity Analysis, pp. 72-74

Treat-
ment

1

Treat-
ment

1

E x rc se 3 2

Sensitivity Analysis

In an area where farmers normally weed their maize only once, it was shown that
a second hand weeding could give higher yields. Researchers estimate that the
opportunity cost of labor is $20/day. Use the data presented below to decide if it is
worth recommending the extra weeding. If the opportunity cost of labor is really
$40/day, what should be the recommendation?

Average yield (one weeding)
Average yield (two weedings)
Yield adjustment
One weeding
Two weedings
Field price of maize
Minimum rate of return

2,450 kg/ha
2,778 kg/ha
10%
14 days/ha
24 days/ha
$1.50/kg
50%

M

4 kEg
:A

Final Exercises

After conducting experiments for several years to explore various research issues,
maize researchers in a certain area designed an experiment to be used in verifying
and demonstrating to farmers the advantages of improved planting density,
fertilization, and insect control. The experiment consisted of 3 treatments, all
managed by the farmer, planted in a single repetition per site. The size of each
plot was 200 m2. Treatments and yields are given below.

In the first year of experimentation in a wheat-growing area, researchers decided
that it would be worthwhile to look at seeding rate by nitrogen interactions.
Farmers were applying nitrogen at low rates (30 kg N/ha) and seeding at 120 kg
seed/ha. The experiments were planted on farmers' fields. The farmers prepared
their plots in the usual way, and researchers planted the experiments and applied
the fertilizer. Farmers used their normal weed control methods. There were 3
seeding rates and 4 levels of nitrogen. The experiment had 3 repetitions per site
and was planted at 5 sites.

Seeding rates: 120, 140, and 160 kg seed/ha

Nitrogen:

Seeding rate
(kglha)

120

140

160

Average

30, 60, 90, and 120 kg N/ha
(The 30 and 60 kg N/ha treatments are a single application at
planting; the 90 and 120 kg N/ha treatments are split applications
at planting and at 30 days.)

Average treatment yields (kglha)

1 2 3- 4
30 Kg N/ha :-6 Kg N/ha 90 Kg N/ha 120 Kg MRt

2,258

2,380

2,241

2,293

2,704

2,587

2,865

2,719

3,117

2,995

3,110

3,074

3,262

3,398

3,019

3,226

Average

2,835

2,840

2,809

2,828

Statistical and agronomic analysis showed increased nitrogen use to be highly
significant and seeding rate not significant; there was no evidence of nitrogen by
seeding rate interaction.

Exercise 33B

U8

Final Exercises

Use the following economic data to do an analysis of this experiment that will help
researchers decide which experiments are appropriate for next year.

The CIMMYT International Maize and Wheat Improvement
Center holds all rights to the source text and shall be
considered the copyright holder for the text and images of
these publications.

The CIMMYT International Maize and Wheat Improvement
Center has made this publication available to the University of
Florida, for purposes of digitization and Internet distribution.

The CIMMYT International Maize and Wheat Improvement
Center reserves all rights to this publication. All uses,
excluding those made under "fair use" provisions of U.S.
Code, Title 17, Section 107 are restricted.

Contact the CIMMYT International Maize and Wheat
Improvement Center for additional information and
permissions.